need help about backfed breakers

walang_problemawalang_problema Registered Users Posts: 9
Good day Sir

I just want to ask about the backfed breakers. is this breaker are the
DPDT(double pole double throw circuit breakers)?... I am not familiar with this type of breakers... In a Grid tied PV systems do they usually uses the bakfed breakers for AC disconnect?... or even a simple air circuit breaker can do?...

it is indicated in NEC 690.64(B)5 SUITABLE FOR BACKFEED. Circuit breakers, if backfed, shall be suitable for such operation.
FTN: Circuit breakers that are marked "line" and "load" have been evaluated only in the direction marked. Circuit breakers without "line" and "load" have beed evaluated in both directions.

I was'nt able to find any of circuit breaker dealers here in the Philippines selling such kind of breakers, some are also not familiar with it... sir do you have something to recommend a dealer/s of backfed breakers...

Thank You Sir...
Have a productive day.. ^_^

Comments

  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: need help about backfed breakers

    Does this help? See: http://www.nmsu.edu/~tdi/pdf-resources/CC111.pdf

    I believe that AC breakers that are not marked "Line" and "Load" are suitable.

    HTH,
    Jim / crewzer
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: need help about backfed breakers

    Yes any breaker that is not marked "line" or "load" can be used. Also note, the back-fed breaker(s) are in a load center must also be clamped.
  • walang_problemawalang_problema Registered Users Posts: 9
    Re: need help about backfed breakers

    sir jim & sir ken

    thank you sir for the help much appreciated, where will I be able to find circuit breakers that has no "LINE SIDE OR LOAD SIDE"...is there any particular manufacturer of back-fed breakers? thanks again sir

    have a nice day
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: need help about backfed breakers

    AC rated breakers generally no not include "Line" and/or "Load" markings.

    Re breaker clamping: Here’s how 2005 NEC 690.64(B)(5) reads:
    “Circuit breakers, if backfed, shall be identified for such operation. Dedicated circuit breakers backfed from listed utility-interactive inverters complying with 690.60 shall not be required to be individually clamped to the panelboard bus bars. A front panel shall clamp all circuit breakers to the panelboard bus bars. Main circuit breakers connected directly to energized feeders shall also be individually clamped.”
    I interpret this paragraph to mean that only backfed circuit breakers connected to the supply side of the of the service disconnect must be individually clamped, and that backfed circuit breakers attached to the load side of the main distribution panel are not required to be individually clamped.

    According to John Wiles, NEC Article 690.3 allows the requirements of 690 to override the clamping requirement of Article 408.36(F). See: http://www.nmsu.edu/~tdi/pdf-resources/CC111.pdf

    HTH,
    Jim / crewzer
  • walang_problemawalang_problema Registered Users Posts: 9
    Re: need help about backfed breakers

    sir jim

    thank you sir

    walang_problema
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